The documents were revealed to the BBC under a Freedom of Information act request.

A City Hall spokesman said: “The deputy mayor for transport works her socks off to make the capital’s transport network more affordable, reliable and accessible for all Londoners.

“Under Sadiq [Khan] and Val, TfL passengers have enjoyed frozen fares and seen a nearly 60 per cent reduction in the number of days lost to strikes.

“If the government shared their drive and gave TfL control of more suburban lines, rail passengers too would get the service they deserve.”

Ms Shawcross did not comment personally.

Image copyrightPAImage caption Val Shawcross was unable to schedule early meetings due to Southern Rail disruptions

The email was among correspondence sent in September from Ms Shawcross’s office to public relations firm Newington Communications, which was arranging a meeting between the deputy mayor and Licensed Taxi Drivers’ Association (LTDA) general secretary Steve McNamara.

The emails revealed that Sadiq Khan said he was too busy to meet Mr McNamara in June and arranged for him to meet Ms Shawcross instead.

Ms Shawcross told the LTDA that she was unable to discuss the Uber relicensing decision with it, which it had requested to do, because doing so with a third party would prejudice TfL’s role as regulator.

On legal advice, she delayed the meeting until after the licensing decision.